Some theories propose that the mental processes that aply knowledge of syntax in sentence comprehension are "guided and constrained" by processes that interpret utterances. Others deny such influences. A larger related question is, does the language comprehension system (possibly reflecting general principles of mental organization) constitute a "module" (or modules) subject ot strict limits on its interactions with other cognitive systems and its access to certain kinds of knowledge? This profject addresses these issues by examining an influence that the pronoun they can exert on the syntactic analysis of ambiguous expressions such as flying planes. The mechanism that exerts this influrence seems to operate at, and thus to illuminate, the interface beetween syntactic and interpretive processing; it seems to be crucially concerned with matters of reference, and yet unalble to use much information that commonly bears on reference. Its application to a given sentence seems to be largely (perhaps, exhaustively) determined by the syntactic structure of the sentence, and yet the work it does look like a preliminary stage of discourse processing. The experiments will use at least three quite different procedures. In one, a naming task, the subject hears a recorded sentence fragment and then, immediately at its end, a word is displayed on the screen of a CRT. The subject reads the word aloud as reapidly as possible. In the second procedure subjects read sentences or short discourses word-by-word, pressing a key to see each new word. Previous experiments have demonstrated that both these tasks are sensitive to the phenomena under study here (see appendices). The third task requires subjects to listen to recorded time-compressed speech. The subject stops the tape at points of their own choosing and recites what has been heard. Previous research indicates that the stopping points subjects choose reflect syntactic structure. By hypothesis, the stopping points will also reflect disruptions related to the phenomena under study in this project. The theorectical questions under consideration have a bearing on a variety of practical matters including, for example, the assessment of reading skills and the design of artificial language understanding systems.